Art of cracking hydrocarbons



June 9,1931. E c. HERTHEL 1,809,297

ART oF CRACKING HYDROCARBONS Filed Feb. 8, 195o l aN-rdR .5l/yen@ C #erf/9 e/ ATTORNEYS Patented e, 1931 UNITED` sTATEsfPATENT omer.

Enemc. Hammam., or rrossmoon, ILLINOIS, AssIGNoa To lsrrrcIaaIisr.r aanname COMPANY, F NEW YORK, N. Y., A. "30RPGRAZLIO11'k 0F MAINE .ABT 0F CRACKING HYDROARBONS lApplication led February 8, 1930. Serial No. 4216,901.

This invention relates to improvements in the manufacture of lower boiling hydrocarbon oils, such as gasoline, from higher boiling hydrocarbon oils, such as gas oil, by pressure '5 cracking operations.

The present invention provides an improved appartaus of special value and application for carrying out the operation described in an application filed June 11th, 1929, by Edward W. Isom and me, Serial No. 370,097 now Letters Patent Number 1,774,601; but the improved apparatus is of general application for carrying out operations in which high boiling oil is heated to a cracking temperature under high pressure and in which the hot oil products of this heating operation are separated into a vapor-ized fraction and an unvaporized fraction under lower pressure, or so-called pressure coil? cracking operations.

The invention will b e described in connection with the accompanying drawings which illustrate, diagrammatically and conventionally, apparatus embodying the invention. In the accompanying drawings, Fig. 1 represents, in elevation and partlyl in section and ,with parts broken away, apparatus embodying the invent-ion, and Fig. 2 is a fragmentar section through and just above the lower en s of the heating tubes illustrated in Fig. 1.

Referring to the drawings, a stream of high boiling oil is forced, by means of pump 2, successively through two batteries of series connected vertical heating tubes arranged in a. vertical heating flue in heating furnace 1,

pors comprising the vaporized fraction are taken oi through connection 13 and are subjected to s. reluxing operation in reflux tower 14 from which the vapors remaining uncondensed escape through connection 15 to a 1 condenser 16 arranged to discharge into a receiver 17 from which a condensed distillate product is discharged through connection l18 and uncondensed vapors and gases through connection 19. Av superatmospheric pressure, lower however than the pressure under which the hot oil products are dischar ed from the second battery of heating tu es, may be maintained in the Ivapor separating receptacle 4 and the reflux tower 14 andregulated by means of valve 20, or by means of Vsuitable 'valves arranged beyond the condenser or receiver. Raw oil or some other refiuxing medium is supplied to therefiuxing operation through connection 21 by means of pump 22, and utilized therein as a direct refluxing medium for effecting and controlling the operation'. Reflux condensate, or admixed reflux condensate and raw oil, is supplied to t-he batteries of heating tubes arranged in the heating furnace 1 from the reiiuxing operat-ion through connections 23 and 11 by means of pump .2. Raw oil, or additional raw oil, may also be supplied to the vapor separating receptacle through connection 24. Residual oil, the vunvaporized fraction separated in the vapor separating receptacle, is discharged from the vapor separating receptacle 4 through connection 25.4

vIn initiating operation, oil, supplied through f connection 2 4, is circulated from the vapor separating receptacle- 4, by means of valved connection 26, through the batteries of heating tubes and back to the vapor1 separating receptacle until normal operating conditions of temperature and pressure are reached, the valve in connection 26 being closed during normal operation. The supply of oil through connection 24 may or may not be continued during normal operation. Connection 27, communicating through valved branches with the lower ends of each of the heating tubes, is provided Jfor pumping out the battery of heating tubes at the en d of a run. The vapor separating receptacle 4 is pumped out at the end of a run through connection 28.

' the general direction of travel of the heatingv nected heating tubes. ,Theseseverllbanks' of heating tubes are arranged transversely to gases entering the upper end of the vertical heatin Hue 7 in whichV these banks of heating tu s` are arranged. lThe heating gases are admitted to one side of the upper end of the vertical heating Hue 7 through passage 8 from the Hrebox 9, in which fuel is burned for supplying heat to the operation, and after passing downwardly through the heating Hue 7 escape from the o posite side of the lower end ofthe heating ue through stack Hue 10. The oil'Howing through each bank of heating tubes Hows successive y upwardlyl and downwardly through the series connected heating tubes forming the bank. The oil supplied to thev twobatteries of heating tubes, through connection 11, Hows first through battery 5 and then through battery 6, being discharged through connection 12. The two batteries of heating tubes, 5 and 6, are separated, or partially separated, by a vertical baHie 29 arranged transversely to the general direction of travel of the heat-ing gases entering the upper end of the heating Hue 7 extending across the heatin Hue 7 but being shorter vertically" than tHe heating Hue 7 and arranged to leave passages across the upper and lower ends of the heating Hue 7. This baHle divides the heating Hue 7 into two Hues, the battery of heating tubes 5 lthrough which the oil first passes bem arranged in the Hue, or sub-Hue, A and the attery of heating tubes 6 throu h which the oil last passes being arrange in the Hue B.' The heating entering the upper end o'f the heating ue 7 from the passage 8 How Hrst across the upper ends of t e banks of heating tubes comprisin the batter 5, then in part through the sub-Hue A `an in part throu h the sub-Hue B downwardly through the eating Hue 7, escaping from the lower end of the heating Hue through stack Hue 10. The proportion of the heating gases Howing through the sub- Hues A and B is determinedb the relative areas of the passages across t e upper and lower ends of the heating Hue 7 directly above and below the upper and lower ends of the baHle 29 respectlvely. All of the heating gases flowing thro h the sub-Hue B, however, are first passe over the heating tubes, or the u per ends of the heating tubes, comprisin e battery 5. The baille 29 ma be ofl any re ry material adapted to wit stand the temperatures maintained in the heatteries of heating tubes, 5 and 6, and the bale 29 in the heating Hue 7 provides an apparatus which is` particularly advantageous for carryingout operations in which high boiling oil is to e brought quickly to a high cracking temperature andV then maintained at that temperature or at a temperature progressively increasing or decreasing therefrom for a Hxed period of time. The improved apparatusof this invent-ion is of special value and application for this purpose and further, in carrying out such operations, assists in minimizing local overheating once the oil is brought to the high cracking temperature and in confning any tendency toward local overheating to a region in which the oil being heated is at a lower mean temperature and in which the cracking has not so far progressed. The arrangement of the heating tubes and the baHle 29 in the heating Hue 7 also provides for unusually low resistance to How of the heating gases through the heating Hue.

In operating the apparatus illustrated, vapors may be taken 0H from the vapor separatlng receptacle 4 under a pressure in the general range Vof 1-10 pounds per-.square inch or under a somewhat higher pressure, for example, and the oil forced through'the batterles of heating, tubes may be heated therein to a temperature approximating 900-1000 F., as discharged therefrom, for example, under a ressure in the general range of 200-600 poun s per square inch, as discharged therefrom, for exam le. The rate at which raw oil, or other re uxing medium, is supplied through connection 21 may be regulated to condense in the reHuxing operation all constituents higher boiling than suitable as comnents of the desired distillate product.

sidual oil ymay be discharged through connection 25 at a fate-,regulated to maintain a uniform liquid level in the vapor separatin receptacle4. Cool raw oil may be supplie `through connection 24,'during normal o eration, to arrest the cracking reaction initiated in the batteries of heating tubes.

The heating furnace 1 may, with advantage, be arranged and operated as described in' Letters Patent Numbers 1,574,546 and 1,574,547, issued to -Sinclair'Relining Company, February 23rd, 1926, on appllcations of the late John E. Bell or as described in Letters Patent Number 1,623,773, issued to Sinclair ReHning Companly, A ril '5th, 1927, on application of the late ohn Bell.

. AlalaA Although the arrangement illustrated has some advantages, particularly structural advantages, it will be a parent that the heating y Hue may be inverted y arranging the admlssion Hue and the stack Hue at its lower and upper ends respectively.

I claim:

1. In apparatus for heating hydrocarbon oils to cracking temperatures, a vertical heating Hue, means for admission of heating gases to one side near the upper end of said heating Hue, vtvvo seriesv connected batteries of series connected banks of series connected vertical heating tubes arranged therein, said banks of heating tubes being arranged transversely to the general direction of travel of heating gases entering through said admission means a vertical baHie separating said batteries of heating tubes arranged transversely to the general direction of travel of heating gases entering through said admission means and extending across said heating Hue but arranged to leave passages across the upper and lower ends thereof, means for escape of heating gases from the opposite side near the lower end of said heating Hue, and means 4for supplying oil to the battery of heating tubes adjacent said admission means and for discharging hot oil products from the other'bat- .30' tery of heating tubes.

2. In apparatus for heating'A hydrocarbon oils tocracking temperatures, a vertical heating Hue, means for admission of heating gases to one side near one end of said heating Hue, two series connected batteries of series connected banks of series connected heating tubes arranged therein, said banks of heating tubes being arranged transversely to the general direction of travel of heating gases en- 40 tering through said admission means, a ver'- tical baHie separating said batteries of heating tubes arranged transversely tothe general direction of travel of heating gases entering through saidadmission means and extending across said heating Hue but arranged to leave passages across the upper and lower ends thereof, means for escape of heating gases from the opposite side near the other end of said heating Hue, and means forsupplying oil to the battery ofheating tubes ad]acent said admission means and for discharging hot oil products from the other battery of heating tubes.

In testimony whereof I aHix my signature. EUGENE C. HERTHEL. 

